OBJECTIVETo compare the concentrations of IgA, lactate dehydrogenase, lysozyme and alkaline phosphatase (ALP) in unstimulated (UWS) and stimulated (SWS) whole saliva between children with severe early childhood caries (S-ECC) and children without caries.

METHODSOne hundred and ninety-two children aged from 42 to 54 months were recruited from 11 urban kindergartens in Beijing. The S-ECC group contained 98 children with more than 5 decayed teeth, and the control group contained 94 caries-free children. The age and sex were matched in the two groups. Two milliliter UWS and 2 ml SWS was collected between 9 and 11 a.m. The salivary IgA was measured by immunoturbidimetric technique. The concentrations of lactate dehydrogenase and ALP were measured by continuous monitoring method, while lysozyme was detected by turbidimetric technique. All results for paired observations between unstimulated and stimulated whole saliva were analysed by paired-samples t test.

RESULTSIn both UWS and SWS, the concentrations of IgA, lactate dehydrogenase and lysozyme in S-ECC children were higher than those in caries-free children (P < 0.01), but the concentration of ALP showed no significant difference in SWS between S-ECC children and caries-free children (P > 0.05).

CONCLUSIONSThe presence of early childhood caries may be associated with an increase of IgA, lactate dehydrogenase and lysozyme in unstimulated and stimulated whole saliva.